This invention pertains to "pots" or traps for capturing crabs and, more particularly, to entrance gate apparatus for allowing entry of crabs into, while preventing escape of crabs from, a crab trap.
One type of crab trap that is in common use today is shown in U.S. Pat. No. 4,184,283 issued to Robert E. Wyman, a coinventor of the entrance gate apparatus disclosed here. Such traps are formed by steel rods welded together to form a generally rectangular box frame structure, the walls of which are formed by nylon netting. As shown in the '283 Patent, entry tunnels, formed by netting, extend inwardly from opposite ends of the trap and terminate in a rectangular frame that is secured to the netting, providing an opening through which the crabs fall into, and to the bottom of, the trap. Bait of pieces of meat such as herring or horse meat is secured by a hook or canister in a central region of such traps.
In recent years, the crab fishing industry has faced declining harvests of crabs and has been subjected to substantially shortened fishing seasons imposed by fishery authorities to preserve the future supply of crabs. To make matters worse, fishery authorities have also been concerned about, and have made allowances for, the effects of the so-called "bycatch" problem that exists when fishing for one crab species results in capture of crabs of other species that are out of season. For example, when fishing for a smaller species, such as the Opilio tanner crab, larger species such as king crab or Bairdi tanner crab are often captured. Handling of such out of season crabs results in a certain mortality percentage for those tossed back into the sea after being removed from the pots. This mortality factor is particularly significant when larger out of season crabs are in the molting state, at which time they are unusually vulnerable to injury. This bycatch mortality problem has prompted fishery closure dates that leave millions of pounds of the established quota for smaller crabs, such as Opilio tanner crabs, unharvested.
Accordingly, it is a specific object of this invention to provide apparatus for selectively preventing the capture of various sized out of season larger crab species while accommodating the capture of the smaller species for which the season is open.
In the past, a great many devices have been proposed for capturing crabs, fish and other animals in a trap. Such devices are described in patents found in U.S. Pat. Office Class 43 and subclasses 100, 101, 102, 103, 104 and 105. For example, U.S. Pat. No. 4,184,283, referred to above, describes resiliently bendable tines to prevent the escape of crabs once they have entered a trap. However, neither this reference nor any other prior art reference of which the inventors are aware, describes an apparatus for selectively preventing the capture of larger crabs or other shellfish while accommodating the capture of smaller species.